tbuckley/cabot-search huggingface dataset:
Abstract P3108: Mouse <i>In Utero</i> Plus Neonatal Sertraline Exposure May Result In A Sex-dependent Risk Of Myocardial Infarction In Adulthood
Authors: Yongjun Lu, Elizabeth Kenkel, Kathy Zimmerman, Robert M Weiss, Robert Roghair, Sarah E Haskell
Journal: Circulation Research (2023)

Background: We previously reported that sertraline reduced left ventricular size, acutely slowed down mouse pup growth, and significantly reduced calcium oscillations in cardiomyocytes (p&lt;0.05), and that the sertraline-induced up-regulations of certain miRNAs might epigenetically modulate cardiac functional gene expression of serotonin signaling pathway with down-regulation of Htr2a, Htr2b and Slc6a4 mRNAs and corresponding proteins (p&lt;0.05). Here we hypothesize that sertraline effect is gender related when subjected to a stress at adult. Method: C57BL/6 adult female mice received sertraline (5 mg/kg/d IP) or saline 5 days before mating, throughout pregnancy until time of delivery, and the pups were given 1/3 adult dose before weaning. At age of 10 weeks, offspring mice were subjected to echocardiograms before myocardial infarction (MI) induced by left anterior descending coronary artery ligation. Mice were divided into groups according to sex, and treatments (saline vs sertraline, &amp; MI vs sham). Ten weeks post-MI, echocardiograms were performed again for the survived mice. Results: Female mice before MI had significantly reduced heart rates (649±18 vs 691±7 bmp), increased end systolic volumes (4.5±0.6 vs 3.2±0.1 μL), and decreased ejection fractions (EF) (80.6±0.7% vs 83.9±0.6%) (n=34, p&lt;0.05). Male mice did not show the significant effects on baseline. Two weeks post-MI, Females had survival rates reduced by sertraline (74.3% vs saline 100%, p=0.0833). Males exhibited MI intolerance with lower survival rates (66.8% vs saline 67.2%), and ODD ratio was deteriorated (24.35 vs female 1.00, p=0.0317). At the end point, the survived mice showed variable MI-induced ischemia zones (47.5±13.2%) corresponding to variable EF (30.0±14.9%). The cardiac functions became not significant different in both male and female survived mice. Concluding Remarks: The cardiac potential risk was observed in the baseline and in the earlier MI phase of female mice with in utero plus neonatal sertraline exposure, while male mice showed different pattern of sertraline effect. Such sex-dependent cardiac effects of maternal SSRI exposure in adult offspring deserve to be detailly studied by using mouse models for heavy use of SSRIs in pregnant women.
Abstract P2016: Extracellular Stiffness Induces Glucose Dysregulation Via Microtubule-dependent Mechanism
Authors: Alexia Vite, Deborah Eaton, Nesrine Bouhrira, Kenneth C Bedi, Kenneth B Margulies
Journal: Circulation Research (2023)

Previous studies have reported profound changes in metabolic fuel utilization pathways during the development of heart failure, including changes in glucose uptake, glucose transporter mislocalization and/or Insulin-resistance. insulin stimulates glucose transport in muscle cells by triggering redistribution of the GLUT4 glucose transporter from an intracellular perinuclear location to the cell surface. Multiple reports have shown that the microtubules in adipocytes and muscle cells play an important role in the insulin-stimulated glucose transport process. We recently demonstrated, using a tunable stiffness substrate mimicking disease myocardium, that we could induces early, cell-autonomous remodeling of adult cardiomyocytes that is dependent on detyrosination of α-tubulin. We therefore employed this culture substrate to define how adult isolated rat cardiomyocytes glucose uptake response is to Insulin when cultured on stiff vs. soft. At the same time, we studied the localization and expression of Glut4 transporter. We found that 48h on stiff substrate was sufficient to induce a loss of insulin sensitivity in our isolated cardiomyocytes. Immunofluorescence reveals a decrease of Glut4 at the Intercalated disc (ID) but show increase of aggregates of the Glut4 transporter at the cell surface. Western Blot analyses shows no change in the total expression of the transporter. Finally, knowing the importance of microtubules network in the trafficking of Glut4, we overexpressed of tubulin tyrosine ligase (TTL) to prevent the detyrosination of microtubules. Surprisingly, TTL not only restored Glut4 at the ID and decreased the number of aggregates, but it also significantly increased glucose uptake as well as the total amount of Glut4 by more than 2-fold compared to soft control. In conclusion, we demonstrated the importance of microtubule dynamics in cardiomyocytes for the Insulin-dependent trafficking of Glut4 to the membrane.
Abstract P1070: In Vivo Autotransplantation Of Spleen-derived Endothelial Progenitor Cells To Promote Angiogenesis In Ischemic Sites
Authors: Seyong Chung
Journal: Circulation Research (2023)

Since mononuclear cells were first illuminated as potential endothelial progenitor cells (EPCs), bone marrow (BM) was extracted and processed as BM-derived EPCs for autotransplantation to the ischemic sites in previous studies. Still, numerous clinical trials based on this strategy showed only marginal effects, and the small number of BM-derived EPCs was suggested as a possible limitation. Meanwhile, spleen contains abundant mononuclear cells which can inherently target the ischemic sites, and these cells can be primed by hypoxia. If only they can be primed in vivo, spleen-derived EPCs can be inherently autotransplanted to ischemic sites with various advantages such as plentiful cell number, non-invasive extraction and delivery of these cells. In this study, splenic mononuclear cells were utilized to promote angiogenesis in ischemic sites. In vivo priming of splenic mononuclear cells, their inherent targeting and therapeutic effect on ischemic sites were sequentially explored towards the 'in vivo autotransplantation'. For hypoxic priming, the effect of hypoxia and hypoxic-mimetic agent (cobalt chloride) on isolated splenic mononuclear cells were comparable in both priming methods, regarding the morphology changes and the increase in expression of EPC markers. In align with these in vitro results, both hypoxic-mimetic agent-loaded nanoparticle delivery to spleen and splenic artery ligation resulted in increased expression of EPC markers in mice spleen. Moreover, the proportion and actual numbers of the cells presenting EPC marker were significantly higher in primed splenic cells than in BM cells. After the priming, these primed cells not only maintained the inherent targeting ability but also gained the ability to promote angiogenesis. Consequently, these primed cells presented therapeutic effects as evidenced by higher expression of angiogenic markers with enhanced blood flow recovery in mouse hindlimb ischemia model, compared with untreated or BM-derived EPCs' autotransplantation for conventional strategy. For EPC-based treatment of ischemia, 'In vivo autotransplantation' is simple and non-invasive strategy which can overcome the previous limitations of insufficient cell numbers.
Abstract P2015: A Human Flii Gene Variant Shortens Sarcomeric Actin Thin Filament Length And Predisposes To Cardiomyopathy
Authors: Yasuhide Kuwabara, Allen York, Suh-chin Lin, Michelle Sargent, Kelly Grimes, James Pirruccello, Jeff D Molkentin
Journal: Circulation Research (2023)

Objective: We identified a human variant in the Flightless-I homolog ( FLII ) gene that generates a R1243H missense change associated with cardiomyopathy in human genome-wide association studies. However, the causality and its molecular mechanism remain unclear. Methods and Results: To examine how the human variant resulting in R1243H amino acid substitution might be pathogenic in vivo, we generated a mouse model harboring the R1245H mutation in Flii locus using CRISPR/Cas9 technology. The Flii R1245H/R1245H homozygotes showed reduced cardiac function by 16 weeks of age compared with control ( P =0.01). Eight-week-old Flii R1245H/R1245H mice subjected to 8 weeks of TAC showed significantly worse cardiac function with greater cardiac hypertrophy and premature lethality compared with control ( P &lt;0.01). Here we show that Flii functions in the heart to regulate sarcomeric actin thin filament length. Indeed, hearts from Flii R1245H/R1245H mice at 16 weeks of age showed reduced thin filament length compared with controls ( P =0.009). To further investigate the mechanistic effects of the R1245H mutation in mouse Flii , we examined actin polymerization dynamics in vitro between wild-type (WT) Flii and the R1245H mutant proteins. The data showed that WT Flii augmented G-actin polymerization into F-actin in a concentration dependent manner, while Flii-R1245H mutant protein antagonized polymerization ( P &lt;0.001). Since LMOD2 is reported to elongate sarcomeric actin thin filaments, we overexpressed LMOD2 using AAV9 system in Flii R1245H/R1245H mice and conducted TAC surgeries at 8 weeks of age. AAV9-LMOD2 rescued the shortening of thin filament length in Flii R1245H/R1245H mice and rescued the exacerbated TAC induced pathology associated with this homozygous mutation (P&lt;0.05). Conclusions: A human FLII variant, R1243H, shortens the sarcomeric actin thin filament, which predisposes to cardiomyopathy. Elongation of thin filament length by LMOD2 overexpression is a possible therapeutic strategy in humans harboring this R1243H mutation.
Abstract P3107: Sexual Dimorphism In Diastolic Dysfunction And Cardiac Small Vessel Disease In Heart Failure With Preserved Ejection Fraction Mouse Models
Authors: Lauriane Cornuault, Virginie Grouthier, Paul Rouault, Célia Bourguignon, Ninon Foussard, Candice Chapouly, Alain-Pierre Gadeau, Thierry Couffinhal, Marie-Ange Renault
Journal: Circulation Research (2023)

Introduction: Coronary microvascular disease has been proposed to be responsible for heart failure with preserved ejection fraction (HFpEF) about 10 years ago. However, to date the role and phenotype of the coronary microvasculature has still been poorly investigated in animal models of HFpEF and sex differences are not always considered. Objective: To characterize the phenotype of the coronary microvasculature in male and female mice with diastolic dysfunction in two HFpEF mouse models. Method: We assessed cardiac function and characterized the coronary microvasculature in mice fed with a high fat diet (HFD) + L-NAME regimen and in Leptin receptor deficient ( Lepr db/db ) mice. Notably, our study was done in males, females and ovariectomized (OVX) female mice in order to search for possible sexual dimorphisms. Results: Upon a HFD + L-NAME regimen, both males and OVX females but not non OVX females develop diastolic dysfunction attested by an increased end diastolic pressure. In Lepr db/db mice, both Male and non OVX female mice develop diastolic dysfunction. Notably female mice have reduced estradiol and progesterone level mice mimicking ovariectomy. We found that both OVX and non OVX females but not males display increased endothelial activation attested by increased ICAM1 expression, endothelium leakage attested by increased Fibrinogen and IgG extravasation and decreased arteriole diameter suggesting vasoconstriction. The same results were found in Lepr db/db mice. Conclusion: Diastolic dysfunction is not always associated with cardiac small vessel disease since Lepr db/db males and C57BL/6J males fed with a high fat diet (HFD) + L-NAME regimen develop diastolic dysfunction in the absence of endothelial dysfunction. Also endothelial dysfunction may not be sufficient to induce diastolic dysfunction since non OVX female mice fed with a high fat diet (HFD) + L-NAME regimen display endothelial dysfunction while they do not develop diastolic dysfunction.
Abstract P2014: Knockout Of Prostaglandin E2 Ep3 Receptor Improves Cardiac Function In Both Sexes In A Mouse Model Of Myocardial Infarction
Authors: Timothy D Bryson, Shaheen Y Bhat, David Taube, Jiang Xu, Edward Peterson, Pamela Harding
Journal: Circulation Research (2023)

Prostaglandin E 2 is an autacoid that acts through 4 G-protein-coupled receptors (EP1-EP4). We previously reported that expression of the EP3 receptor increases after myocardial infarction (MI) and mediates reduced cardiac function. This effect was exacerbated in mice that overexpress EP3 in the cardiomyocytes. Furthermore, we reported that the EP3 receptor antagonist, L798106 reduced blood pressure in the Angiotensin II hypertension model and improved cardiac function. We therefore hypothesized that cardiomyocyte specific knock-out of EP3 (EP3 KO) and/or pharmacological antagonism of EP3 protects the heart from cardiac dysfunction after MI. To test our hypothesis, we created a cardiomyocyte specific (αMHC promoter), tamoxifen inducible CM-EP3 KO mouse. Fifteen-week-old male and female EP3 KO and floxed controls underwent sham or MI surgery. After 2 wks, echocardiography was performed, and all statistical analysis was performed by a biostatistician at Henry Ford Health. There were no significant differences in cardiac function between strains after sham operation. After 2 wks MI, male floxed control mice showed significant reductions in ejection fraction (EF;68 ± 5.6 % sham vs 49.1 ± 5.2 % MI; p&lt;0.05), coupled with increased left ventricle dimension at systole (LVDs;1.12 ± 0.08 mm sham vs 2.08 ± 0.34 mm MI; p&lt;0.05). Remarkably, however, these changes were not observed for EP3 KO mice post-MI. EF was 73.1 ± 0.68% in sham vs 69.0 ± 0.81% for MI; and LVDs was 1.09 ± 0.05 in sham vs 1.09 ± 0.04 for MI. Similarly, EF was 66.3 ± 2.4% in female sham mice and remained unchanged after MI (EF; 62.7 ± 2.3% in EP3 KO MI). To investigate a more translational and therapeutic approach, we examined whether daily administration of L798106 improves cardiac function post MI. Male C57BL/6 mice were subject to MI and assigned to vehicle or L798106 treatment (40 μg/Kg/day, s.c.) beginning 3 days post-surgery. After 2 wks, EF was substantially improved from 36.0 ± 2.6% in vehicle vs 49.4 ± 3.0% in L798106, p&lt;0.01. Similar improvements were observed in fractional shortening. Altogether, these data suggest that EP3 may play a direct role in regulating cardiac function and future experiments are warranted to investigate the use of an EP3 antagonist as a potential therapeutic in heart failure.
Abstract P2018: In Vivo Imaging Of The Coronary Microcirculation Throughout The Contractile Cycle With Optical Coherence Tomography Angiography
Authors: Yirong Zhou, Junyoung Kim, Aaron D Aguirre
Journal: Circulation Research (2023)

Introduction: Studying coronary microvascular disease (CMD) warrants in vivo high-resolution microcirculation imaging, which requires advanced motion correction and gating strategies. We hypothesized that cardiac and respiratory gating and custom angiogram reconstruction algorithms may enable label-free optical coherence tomography angiography (OCTA) of the coronary microcirculation in vivo in mice throughout the cardiac cycle. Methods: C57BL/6 male mice (n=20) were imaged through a sternotomy while anesthetized and ventilated. OCTA was performed using a custom tissue stabilizer and a Thorlabs TEL 321 OCT system, which was synchronized to physiologic signals using custom hardware and software and cardiac pacing protocols (Fig. 1A). Angiograms were created by calculating speckle variance between images with one of two strategies: 1. Images within the same cardiac cycle (AB method); or 2. Images in two different cardiac cycles (AC method). Angiograms were formed during both diastole and systole (Fig. 1C and E). Data were processed in MATLAB and ImageJ. Results: Without gating or stabilization, angiograms cannot be produced (Fig. 1B). Using stabilization with custom gating and reconstruction strategies significantly improved image registration (Fig. 1G) and allowed creation of widefield capillary angiograms without exogenous contrast agent during both diastole and systole (Fig. 1D and F). Conclusion: In vivo OCTA can image the coronary microcirculation in the heart throughout the cardiac cycle and will provide a powerful new tool for investigating coronary microvascular dysfunction in mouse models of heart disease.
Abstract P2047: Fast Skeletal Myosin Binding Protein-C Expression Exacerbates Dysfunction In Heart Failure
Authors: Taejeong Song
Journal: Circulation Research (2023)

Background: During heart failure, gene and protein expression profiles undergo extensive compensatory and pathological remodeling. We have previously observed that fast skeletal myosin binding protein-C (fMyBP-C) is upregulated in diseased mouse hearts. While fMyBP-C shares significant homology with its cardiac paralog, cardiac myosin binding protein-C (cMyBP-C), there are key differences in the functional differences which may affect cardiac function. Also, it is unknown if the fMyBP-C expression in the heart is a pathological or compensatory response. Objectives: We aim to elucidate the consequence of increased fMyBP-C expression in the heart. Methods: To determine the sufficiency of fMyBP-C to cause cardiac dysfunction, we generated cardiac-specific fMyBP-C over-expression mice. These mice were further crossed into a cMyBP-C null model to assess the effect of fMyBP-C in the heart in the absence of cMyBP-C function. Finally, fMyBP-C knockout mice were subjected to transverse aortic constriction (TAC) to define the requirement of fMyBP-C during heart failure development. Results: We confirmed the upregulation of fMyBP-C in several models of cardiac disease. Genetic over-expression of low levels of fMyBP-C caused mild cardiac remodeling and sarcomere dysfunction. High expression of fMyBP-C in a heart failure model further exacerbated the cardiac disease, hypertrophy and fibrosis. On the other hand, following 8 weeks of TAC, fMyBP-C null mice demonstrated greater protection against heart failure development. Mechanistically, this may be due to the greater instability of the myosin super-relaxed state compared to wild-type littermates. Conclusions: These findings suggest that the elevated expression of fMyBP-C in diseased hearts is a pathological response. Targeted therapies to prevent upregulation of fMyBP-C may prove beneficial in the treatment of heart failure.
Abstract P2135: A Novel <i>Pkp2</i> Mouse Model Of Genetic Arrhythmogenic Right Ventricular Cardiomyopathy And Its Rescue By Gene Therapy
Authors: Emma Xu, Melissa Van Pell, Aliya Zeng, Amara Greer-Short, Cindy Li, Ze Cheng, Iris Wu, Xiaomei Song, Samantha Jones, Kathy Ivey, Jin Yang, Laura Lombardi, Tim Hoey, Jane Yang
Journal: Circulation Research (2023)

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder in which cardiomyocytes lack structural integrity and signaling is compromised resulting in the disruption of normal rhythms and formation of fibrosis. Patients suffer from arrhythmia and are at increased risk of sudden cardiac death and heart failure. Previous work has demonstrated that heterozygous mutations in the desmosomal gene, plakophilin-2 ( PKP2 ), are the most common cause of ARVC. Our objective was to investigate the mechanisms of ARVC development and test a potential ARVC gene therapy strategy using a novel mouse model of Pkp2. Methods: A knock-in (KI) mouse model with a point mutation corresponding to human PKP2 ( PKP2 c.2146-1G&gt;C or Pkp2 KI) was generated via CRISPR/Cas9 technology. High fat diet (HFD) was used to induce the ARVC phenotype in the Pkp2 KI heterozygous (het) mice. The Pkp2 KI het mice were crossed with a cardiac-specific Pkp2 cKO (αMHC-Cre ERT ) mouse to generate a tamoxifen inducible model (KIxKO). Cardiac function was assessed by echocardiography and arrhythmia burden by EKG. The KIxKO animals received AAV:PKP2 via retro-orbital injection. Results: Pkp2 KI het animals with normal chow had slow and mild ARVC development, and 50% decrease in PKP2 protein expression, with right ventricle (RV) dilation not occurring until animals were 9 months old. Induction with HFD from 8 weeks hastened and worsened the RV dilation. In contrast, the KIxKO mice exhibited &gt;90% decrease in PKP2 protein expression and a correspondingly severe ARVC phenotype starting from 3 weeks after Tamoxifen induction. This included a high arrhythmia burden and both RV area dilation and decreased ejection fraction, indicating the mice eventually progressed to biventricular heart failure. This resulted in 100% mortality in KIxKO animals by 9 weeks post-tamoxifen induction. A single dose of AAV:PKP2 gene therapy (6E13 vg/kg) maintained ejection fraction, prevented ARVC development and improved survival in the KIxKO mice after 9 weeks of treatment. Conclusion: The current results demonstrated that AAV:PKP2 gene therapy may be a promising therapeutic approach to treat ARVC patients with PKP2 mutations resulting in haploinsufficiency.
Abstract P2132: The Raf Kinase Inhibitor Protein Protects Mitochondria From Ischemic Stress
Authors: Theresa Brand, Ann-Kathrin Lukannek, Christian Kautz, Constanze Schanbacher, Nilgün Gedik, Petra Kleinbongard, Kristina Lorenz
Journal: Circulation Research (2023)

Background: The Raf kinase inhibitor protein (RKIP) increases cardiac inotropy without detrimental remodeling and even protects from the development of heart failure in response to chronic pressure overload or catecholamines. These RKIP effects are mediated via simultaneous and persistent activation of cardiac β1- and β2-adrenergic receptors (βAR). Hypothesis: Since an intact mitochondrial function is central for the energy supply and cardiomyocyte health, which are parameters that had been proven to be positively influenced by RKIP in the heart, we here aimed to analyze the impact of RKIP and βAR signaling on mitochondria. Methods and Results: Electron microscopy, respiration measurements and confocal analysis of the mitochondrial membrane potential (mtMP) revealed that the mitochondria of RKIP knockout mice are of smaller size and abnormal shape, show a reduced ADP-stimulated respiration and a hyperpolarized mtMP compared to WT mitochondria. And, expression levels of several respiratory proteins were reduced. In contrast, mitochondrial content in RKIP-tg mouse hearts was enhanced, mitochondrial function maintained, and expression of proteins involved in respiratory complexes and mitochondria-related transcription (e.g. Tfam, NRF-1) was enhanced. To evaluate the stress resistance of RKIP-tg hearts, we subjected isolated cardiomyocytes or hearts of RKIP-tg or WT, respectively, to ischemia/reperfusion (I/R) stress. I/R effectively decreased the mtMP in WT cardiomyocytes and impaired ADP-stimulated respiration of isolated WT mitochondria after ex vivo I/R. In contrast, RKIP-tg mitochondria were protected from mtMP collapse and impaired respiration after I/R. To understand this protective RKIP-mediated effect and whether βAR are involved, we analyzed mtMP in neonatal cardiomyocytes of β2AR knockout mice, upon application of different βAR ligands, pertussis toxin and inhibitors of the PI3K or AKT. These experiments suggest a RKIP-mediated mitochondrial protection via β2AR/Gi/PI3Kα/pAKT signaling. Discussion: Our study shows that RKIP-βAR signaling protects mitochondria from I/R stress suggesting βAR modulation as a potential therapeutic strategy to protect the myocardium in ischemic conditions.